The present invention relates, in general, to a switching device.
The following discussion of related art is provided to assist the reader in understanding the advantages of the invention, and is not to be construed as an admission that this related art is prior art to this invention.
Switching devices of a type involved here disconnect a line network from the power grid in the event of a short-circuit in the line network to prevent further supply of electric current. Such switching devices therefore have a so-called short-circuit trigger device which, when triggered, triggers a mechanical disconnect device which disconnects the switching contacts of the switching device, thereby preventing additional current flow. Typically, the short-circuit trigger device operates mechanically on a mechanical trigger of the disconnect device.
Short-circuit trigger devices are predominately implemented as an electromagnetic device, for example, as an elongated cylindrical coil with an armature arranged inside the coil. In the event of a short-circuit, the current reaches several thousand amperes, causing the armature to move, thereby triggering the disconnect device. Disadvantageously, short-circuit trigger devices with an elongated cylindrical coil have a complex structure which is expensive to manufacture, and also require support for the armature inside the coil.
It would therefore be desirable and advantageous to provide an improved switching device which obviate prior art shortcomings and are simple in structure and yet reliable in operation.